Hitherto, a ceramic has been used extensively as a material having a good resistance to heat and a high degree of hardness. Such a ceramic is prepared by admixing raw materials such as alumina or the like and molding it, followed by sintering. The ceramic can be formed into various shapes upon molding so that it can be used for wide purposes.
Alumina as a representative ceramic has thermal properties including heat resistance of approximately 1,600° C., thermal conductivity of 36.0 (W/m/K), and a heat diffusion coefficient of 0.0119×103 (m2/s) (each value being measured at 300 K).
Although the conventional ceramic as described above has been used in a wide range of fields due to its heat resistance, anti-wearing property, readiness for processing and so on, the development of an artificial raw material having further improved thermal properties such as heat resistance has been desired.
Moreover, the conventional ceramic as described above has to be sintered after molding a mixture of the raw materials so that it requires a long time and a labor for the preparation thereof. Therefore, the development of an artificial ore easy for preparation has been desired.